1. Field of the Invention
The present invention relates to a method and corresponding apparatus and system for identifying a specific part, in particular a specific vertebra, of a spine in an image, in particular a computed tomography (CT) image, of a human or animal body.
2. Description of the Related Art
The acquisition of CT images with and without contrast agent of abdomen, thorax and/or neck is a routine procedure for the diagnosis of a multitude of diseases or injuries. The spinal column represents a natural reference structure of the upper part of the body for describing the locations of organs and pathologies. To be used as a reference system in daily clinical routine, the vertebrae and/or intervertebral disks in the image have to be labeled. A manual labeling can be time consuming, especially if only arbitrary parts of the spine are visible in the data. Therefore, automatic approaches which deliver labeling results after image acquisition without any user interaction are of interest.
When automatically labeling thorax/lumbar portions of a spine in CT scans it is necessary to assign a correct anatomic intervertebral disc label to a starting point. For example, being the bottommost vertebra with ribs, the T12 vertebra and its associated intervertebral discs are natural candidates for starting points of a spine labeling algorithm. It turned out, however, that a reliable discrimination of the T12 vertebra from other vertebrae in a lumbar-thoracic CT scan is not trivial and can even become hard especially in partial scans, i.e., when image data showing only some of lumbar and/or some of thoracic vertebrae. The ribs attached to the T12 vertebra vary in length and form and may exhibit anatomical similarity with the transversal processes of the L1 vertebra. This may confuse even domain experts and will generally bias any unaware attempts on automated initialization of the labeling algorithm from T12.